Selenium Effectively Reduces Insulin Resistance in Subjects with Cardiometabolic Diseases

by | Jan 17, 2023 | 2022, Cardiovascular Health, Diabetes, Kidney Health, Minerals, Selenium

Written by Taylor Woosley, Staff Writer. Results of a meta-analysis of 10 randomized controlled trials including 526 participants shows that selenium supplementation significantly reduced serum insulin levels (p=0.001), decreased HOMA-IR (p=0.006), and increased HDL-C levels (p =0.007). 

seleniumCardiometabolic diseases (CMDs), including cardiovascular diseases, type 2 diabetes mellitus, and chronic kidney disease, are the leading causes of death worldwide1. Low-grade chronic inflammation represents a key pathophysiological mechanism of the disease2. CMDs stem from various factors, including genetics, environmental factors, and insulin resistance3. Chronic insulin imbalance inhibits nitric oxide production leading to endothelial dysfunction4.

Selenium is an antioxidant trace element that plays important biological roles in the human body5. Selenium function is required for antioxidant defense, prevention of inflammation, and DNA synthesis6. Previous studies have suggested that Se supplementation, through inhibiting the production of advanced glycation end products, and decreasing the free radical production and lipid hydroperoxide, could affect inflammatory mechanisms such as insulin resistance, glucose homeostasis and oxidative stress7.

Ouyang et al. conducted a systemic review and meta-analysis to examine the effect of selenium supplementation on glucose and lipid metabolism in CMDs. Study inclusion criteria consisted of randomized controlled trials containing subjects with CMD-related diseases, with a selenium supplementation treatment group, with the primary outcomes of insulin levels. Final analysis included 10 randomized controlled trials, and all were double-blind, placebo-controlled trials. There were 526 participants overall, with 272 in the selenium group and 254 in the control group. Treatment periods ranged from 4 to 24 weeks.

Study heterogeneity was assessed using Cochrane’s Q test and was quantified by I2 test. In instances where heterogeneity was noted among studies, subgroup analysis or sensitivity analysis were performed to assess its possible sources. All 10 studies analyzed the effects of serum insulin levels and homeostatic model assessment of insulin resistance (HOMA-IR). Nine studies evaluated the effects of selenium supplementation on fasting plasma glucose (FPG) and HDL-C. Significant findings of the meta-analysis are as follows:

  • The heterogeneity of HOMA-IR and serum insulin levels were moderate (I2=68%, I2=75%). Pooled results using a random-effects model demonstrated that selenium supplementation significantly lowered serum insulin levels (SMD: -53, 95% CI [-0.84, -0.21], p = 0.001) and decreased HOMA-IR (SMD: -0.50, 95% CI [-0.86, -0.14], p = 0.006).
  • Regarding selenium supplementation on FPG, the heterogeneity between studies was high (I2=91%). Pooled analysis using the random effects model indicated that both the selenium and control group had similar effects on FPG (SMD: 0.06, 95% CI [-0.56, 0.68], p = 0.86).
  • Pooled results from the random-effects model indicated that selenium supplementation significantly increased HDL-C levels (SMD: 0.97, 95% CI [0.26, 1.68], p = 0.007), with high heterogeneity across studies (I2=92%).

Results of the meta-analysis show that selenium supplementation improved serum insulin levels and HOMA-IR. Furthermore, selenium appeared to increase HDL-C levels, suggesting that selenium may effectively reduce insulin resistance in subjects with CMDs. Study limitations include the inability to determine the optimal dose of selenium supplementation, the relatively low number of participants, and the lack of studies evaluating the efficacy of selenium on HbA1c levels.

Source: Ouyang, Jiahui, Yajie Cai, Yewen Song, Zhuye Gao, Ruina Bai, and Anlu Wang. “Potential Benefits of Selenium Supplementation in Reducing Insulin Resistance in Patients with Cardiometabolic Diseases: A Systematic Review and Meta-Analysis.” Nutrients 14, no. 22 (2022): 4933.

© 2022 by the authors.Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

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Posted January 17, 2023.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

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